Log Message:
Update xmlstarlen from 1.3.1 to 1.6.1

Local changes:
 - reuse upstream INSTALL_TARGET dirs
 - depend on documentation installed by default

Upstream changelog
==================
1.6.1: August 9, 2014

    - handle unicode arguments under Windows

1.6.0: June 12, 2014

    - get rid of "helpful" message about namespaces
    - update user guide
    - Enhancements:
      - add --stop option to val
      - add global option --no-doc-namespace
    - Build:
      - let the make install target succeed even if docs aren't built.

1.5.0: Jul 7, 2013

    - Bugs:
      - avoid segfault on pyx non-existant file
      - fix unescaping of entities straddling 4K byte boundary (Bug #102)
    - Enhancements:
      - unescape hex entities (&#xXX;)
      - give a helpful message if doc has default namespace and
        nothing matched
      - add "_" and "DEFAULT" as names for document's top-level
        default namespace
      - Adding a global quiet option
      - ed: Allow omitting value argument to create empty element.
      - use default attribute values in sel subcommand
    - Build:
      - fix test variables to work with newer automake (1.11 -> 1.13)
      - fix usage2c.awk for mawk
      - scripts for building on mingw

1.4.2: Dec 28, 2012

    - pyx: avoid segfault on documents with multiple attributes (Bug
      #3595212)

1.4.1: Dec 8, 2012

    - avoid segfault when attempting to edit the document node (Bug
      #3575722)

    - Packaging:
      - include doc/xmlstar-fodoc-style.xsl in the dist so that the
        --enable-build-docs option works from the tarball (Bug
        #3580667)
      - AC_SUBST PACKAGE_TARNAME for automake so that documentation is
        installed to the right place (Bug #3561958)

    - Test Suite:
      - avoid test failures due to XML formatting and whitespace
        changes (also fixes Bug #3572789)
      - use automake's parallel test suite
      - make bigxml tests much faster by using whitespace instead of nodes
      - don't test str:replace() with ed: it doesn't work outside of
        xslt in new libxslt
      - ignore extra errors from libxml 2.9.0 bug
      - let tests run using busybox
      - add runAllTests.sh to run tests without make

1.4.0: Aug 26, 2012

    - Documentation:
        - executable name used in documentation now matches
          --transform-program-name (Bug #3283713)
        - added Makefile rules for generating documentation
          (./configure --enable-build-docs)

    - ed subcommand:
        - relative XPaths are now handled correctly (Bug #3527850)
        - the last nodeset inserted by an edit operation can be
          accessed as the XPath variable $prev (or $xstar:prev)
        - add --var option to define XPath variables
        - allow ed -u -x to insert nodesets instead of converting to
          string
        - remove hard limit for number of edit operations (Bug
          #3488240)

    - pyx now handles namespaces correctly